W
- The type of Window
that this assigner assigns.public abstract class WindowAssigner<W extends Window> extends Object implements Serializable
WindowAssigner
assigns zero or more Windows
to an element.
In a window operation, elements are grouped by their key (if available) and by the windows to
which it was assigned. The set of elements with the same key and window is called a pane. When a
Trigger
decides that a certain pane should fire the window to produce output elements for
that pane.
Constructor and Description |
---|
WindowAssigner() |
Modifier and Type | Method and Description |
---|---|
abstract Collection<W> |
assignWindows(RowData element,
long timestamp)
Given the timestamp and element, returns the set of windows into which it should be placed.
|
abstract TypeSerializer<W> |
getWindowSerializer(ExecutionConfig executionConfig)
Returns a
TypeSerializer for serializing windows that are assigned by this WindowAssigner . |
abstract boolean |
isEventTime()
Returns
true if elements are assigned to windows based on event time, false
otherwise. |
void |
open(InternalWindowProcessFunction.Context<?,W> ctx)
Initialization method for the function.
|
abstract String |
toString() |
public void open(InternalWindowProcessFunction.Context<?,W> ctx) throws Exception
Exception
public abstract Collection<W> assignWindows(RowData element, long timestamp) throws IOException
element
- The element to which windows should be assigned.timestamp
- The timestamp of the element when isEventTime()
returns true, or
the current system time when isEventTime()
returns false.IOException
public abstract TypeSerializer<W> getWindowSerializer(ExecutionConfig executionConfig)
TypeSerializer
for serializing windows that are assigned by this WindowAssigner
.public abstract boolean isEventTime()
true
if elements are assigned to windows based on event time, false
otherwise.Copyright © 2014–2021 The Apache Software Foundation. All rights reserved.